Perhaps you should try some spelling variations:
qua cham » qua hai, qua cac, va cham
cham loc » cham soc, chon loc, cham o
vanh dai » van dai, vanh tai, lanh dao
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
va vanh » va van, va danh, va hanh
loc va » hoc va, luc va
cua te » cua tu
o hoi » co hoi, o hoc, o hoa
o hai » co hai, so hai, o lai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((o hoi) OR (o hai)). hieu qua cham loc va vanh dai cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((o hoi) OR (o hai)). hieu qua cham loc va vanh dai cua te*".